Get the chars field from a regex-charset.
This is an ordinary field accessor created by defprod.
Function:
(defun regex-charset->chars$inline (x) (declare (xargs :guard (regex-p x))) (declare (xargs :guard (equal (regex-kind x) :charset))) (let ((__function__ 'regex-charset->chars)) (declare (ignorable __function__)) (mbe :logic (b* ((x (and (equal (regex-kind x) :charset) x))) (acl2::str-fix (std::da-nth 0 (cdr x)))) :exec (std::da-nth 0 (cdr x)))))
Theorem:
(defthm stringp-of-regex-charset->chars (b* ((chars (regex-charset->chars$inline x))) (stringp chars)) :rule-classes :type-prescription)
Theorem:
(defthm regex-charset->chars$inline-of-regex-fix-x (equal (regex-charset->chars$inline (regex-fix x)) (regex-charset->chars$inline x)))
Theorem:
(defthm regex-charset->chars$inline-regex-equiv-congruence-on-x (implies (regex-equiv x x-equiv) (equal (regex-charset->chars$inline x) (regex-charset->chars$inline x-equiv))) :rule-classes :congruence)
Theorem:
(defthm regex-charset->chars-when-wrong-kind (implies (not (equal (regex-kind x) :charset)) (equal (regex-charset->chars x) (acl2::str-fix nil))))